Segmented Piston Assembly With Radial Gap to Reduce Wear

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Solution Overview

Problem

Conventional piston assemblies face structural integrity issues due to extreme operating conditions, limiting the replacement of OEM components with aftermarket improvements, particularly in reciprocating compressors where galling and wear occur, restricting the extension of operational life.

Innovation Solution

A piston assembly design featuring a piston rod with first and second lands supporting frame and outer end caps, and a center support with a radial gap, allowing for improved alignment and support of piston components, enabling easier replacement and reduced wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional three-piece piston design is used, then piston assembly can operate in extreme conditions, but galling and wearing occur reducing structural integrity

Engineering Contradiction:
Improvestructural integrityVSAvoidoperational life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The piston is divided into multiple separable components including a piston rod, end caps, and a center support section. This segmentation allows individual components to be replaced independently based on wear patterns, extending the overall operational life while maintaining structural integrity of the remaining components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design introduces a radial gap between the piston rod and center support, creating a clearance parameter that reduces contact and friction. This parameter change mitigates galling and wearing by minimizing direct metal-to-metal contact under extreme operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If OEM components are replaced with aftermarket components, then operational life can be extended, but design limitations restrict replacement ability

Engineering Contradiction:
Improveoperational lifeVSAvoidcomponent replaceability
Core Design Contradiction:
Duration of action of moving objectVSAdaptability or versatility

Solution Approach 1:

The segmented piston design with separable end caps and center support enables selective replacement of worn components with improved aftermarket parts. Each segment can be independently sourced, manufactured, and installed, greatly enhancing adaptability and versatility in component replacement strategies.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The piston components are designed with nested through-bores that receive the piston rod, creating a telescopic assembly. This nested configuration allows for easy disassembly and reassembly with different component variations, facilitating flexible aftermarket replacements while maintaining proper alignment and fit.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Stability of the object's composition

If conventional piston design with three lands is used, then sufficient alignment and support are achieved, but component replacement is limited

Engineering Contradiction:
Improvealignment and supportVSAvoidcomponent replacement
Core Design Contradiction:
Stability of the object's compositionVSEase of repair

Solution Approach 1:

By segmenting the piston into replaceable sections with through-bores for the piston rod, the design maintains alignment and support stability through precise reassembly of segmented components, while simultaneously enabling easy repair and component replacement that conventional integrated designs do not allow.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3237780B1Piston assembly
Publication Date: 2022.03.09 DRESSER RAND CO
  • EP3237780B1 patent drawingFigure 1A
  • EP3237780B1 patent drawingFigure 1B
  • EP3237780B1 patent drawingFigure 2

AI summary

A piston assembly may include a piston rod and a piston disposed on the piston rod. The piston may include a frame end cap defining a through-bore for receiving the piston rod, and the frame end cap may form a first end of the piston. The piston may include an outer end cap defining a through-bore for receiving the piston rod, and the outer end cap may form a second end of the piston. The piston may also include a center support defining a through-bore for receiving the piston rod. The center support may be disposed between the frame end cap and the outer end cap, and an outer surface of the piston rod and an inner circumferential surface of the center support may define a radial gap.